Apparatus having invertable metering chamber

ABSTRACT

A wear-testing apparatus comprising a pneumatic system for feeding and discharging abrasive particles against a test specimen. The system includes a metering device having an adjustable gauge tube for measuring a charge of abrasive particles. An orifice is provided at the outlet end of the gauge tube for metering the rate of discharge flow of such charge at a controlled rate into the pneumatic feed system. The system includes a discharge nozzle utilizing a venturi tube for feeding the abrasive particles through the system and blasting the same against the test specimen. An elastic collar engageable with the surface of the test specimen, is mounted on the outlet end of the nozzle for confining the spent abrasive particles within the blast area and for recovering and collecting the spent particles.

O United States Patent 1 3,592,362

[72] Inventor Kenneth G. KaneY 1,560,013 1 H1925 Angeletti 222/363 Cheektowaga, N. 1,993,693 3/1935 Tanner 222/308 X [21] Appl. No. 803,359 3,140,018 7/1964 Miller 222/363 X 7 med Primary Examiner-J-larvey C. Hornsby [45] Patented July [3, l97l A: E H S [73] Assignee Pin Point Products Inc. A slant gg'l l Lane amino NY. ttorneyrlste & Bean 1541 APPARATUS HAVlNGlNVERTABLE METERING W A 'i P j a P CHAMBER matic system for feedmg and discharging abrasive particles 8 Chi 9 on" in g against a test specimen. The system lncludes a metering device haying an adjustable gauge tube for measuring a charge of U-S. abrasive partlqles An orifice is provided at the outlet end of 222/334 the gauge tube for metering the rate of discharge flow of such ill. charge at a controlled rate into the pneumatic feed ystem, of The system includes a dlsch ge noule utilizing a venturi tube 222/454, 148, 193, 305, 306, 307, 30 for feeding the abrasive particles through the system and blast- 366, 334 ing the same against the test specimen. An elastic collar engageable with the surface of the test specimen, is mounted on [56] Reknnm cued the outlet end of the nozzle for confining the spent abrasive UNITED STATES PATENTS particles within the blast area and for recovering and collect- 874,757 12/1907 Fox 222/308 ing the spent particles.

llll APPARATUS uAvrNc INVERTABLE METERING CHAMBER BACKGROUND OF THE INVENTION This invention relates to an apparatus for measuring wear and the abrasion resistance of articles of manufacture, and more particularly, to a device for metering abrasive grit in such an apparatus.

Wear and abrasion resistance is one of the most important factors in the service performance of certain abrasive elements, such as grinding wheels for example. It is desirable to determine as closely as possible the wear and abrasion resistance characteristics of various grinding wheel compositions for comparing the same and choosing the most suitable wheel composition for a given job. Also, the measure of wear and abrasion resistance of these abrasive elements is important for quality control.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved wear-testing apparatus for obtaining an indication of the wearing and abrasion resistance qualities of test specimens.

It is another object of this invention to provide the foregoing with novel means for metering a charge of abrasive particles which is blasted against the test specimens.

In carrying out this invention, the improved wear testing apparatus of the present invention comprises a pneumatic system for feeding and discharging abrasive particles against test specimens. The system incorporates a novel metering device having a gauge tube for measuring a predetermined charge of abrasive particles to be applied against the test specimen. An orifice is provided in the gauge tube for metering the discharge flow of such charge at a controlled rate through a pneumatic feed system. The system includes a discharge nozzle utilizing a venturi tube for feeding the abrasive particles through the system and discharging the same against the test specimen. Means are provided on the nozzle for confining the particles within the blast area for recovering and collecting the spent particles.

The foregoing and other objects, advantages and characterizing features of the present invention will become clearly apparent from the ensuing detailed description of a certain illustrative embodiment thereof, taken together with the accompanying drawings wherein like reference numerals denote like parts throughout the various views.

BRIEF DESCRIPTION OF THE DRAWING FIGURES FIG. 1 is an elevational view of a wear-testing apparatus of the present invention;

FIG. 2 is an enlarged vertical sectional view of a discharge nozzle of the foregoing invention;

FIG. 3 is a fragmentary side elevational view of a metering mechanism of this invention and the actuating means therefor;

FIG. 4 is a top plan view of the mechanism shown in FIG. 3;

FIG. 5 is a rear elevational view of the mechanism of FIG. 3;

FIG. 6 is an enlarged vertical sectional view thereof taken about on line 6-6 of FIG. 4;

FIG. 7 is a horizontal sectional view taken about on line 77 of FIG. 6;

FIG. 8 is a horizontal sectional view taken about on line 8-8 of FIG. 6; and

FIG. 9 is a fragmentary vertical sectional view of a portion of the metering mechanism ofthis invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now in detail to the drawings, there is shown in FIG. 1 a wear-testing apparatus of the present invention comprising a supporting frame, generally designated 10, having a -work table 12 supported by legs 14. A support arm I6 extends laterally outwardly from table 12 and is pivotally mounted thereto about a vertical pivot axis as at 18.

Mounted on table 12 is a parallelogram linkage, generally designated 20, comprising a pair of elongated, upwardly extending arms 22 and 24 mounted for pivotal movement about horizontally oriented pivot pins 26 and 28. Suitable counterweights 27 are provided on the lower end of arm 24, the member of weights 27 and their position on arm 24 being varied to balance the pivotable linkage above table I2. The other end of arms 22 and 24 are pivotally connected to a bracket 30 about horizontally extending pivot pins 32 and 34. Also mounted on bracket 30 is a parallelogram linkage, generally designated 36, having a pair of elongated arms 38 and 40 mounted at their one end for vertical pivotal movement about horizontally extending pivot pins 42 and 44 mounted in bracket 30. Suitable counterweights 43 are providcd adjacent the free end of arm 40. The other end of arms 38 and 40 are pivotally connected as by means of pivot pins 46 and 48 to a support bracket 50. Suitably secured to bracket 50 is an abrasive grit discharge nozzle, generally designated 52, for a purpose hereinafter more fully explained. Parallelogram linkages 20 and 36 enable nozzle 52 to be easily moved in horizontal and vertical directions relative to worktable I2.

A support plate 54 is mounted below worktable 12 on legs 14 as by means of screws 56 for example. Plate 54 terminates in an extension 58 having an elongated plate 57 secured to one side thereof. Attached to plate 54 by suitable fasteners, such as screws 59, is a fluid-actuated cylinder 50 having a piston 62 connected to a piston rod 64. A connecting rod 66 is secured at one end thereof to piston rod 64 by means of a pin 68, the other end of rod 66 having bifurcations 70 straddling a drive pulley 72 and connected thereto by means of pin 74. Drive pulley 72 is rotatably mounted on plate 54 by means of a bolt 76 extending through a washer 78, bushing 80, thrust bearing 82, and plates 54 and S7 and threadably received in a nut 86. A drive cable 88 is adjustably secured about drive pulley'72 and wrapped through a plurality of turns about a spool 90 extending laterally through extension 58 and plate 57 and rigidly secured within a metering mechanism, generally designated 92 by means of a pin 93. A tension coil spring 96 is secured at one end to a drive pulley 72 and at the other end to an eye bolt 98 adjustably mounted by means of lock nuts 100 in an angle member 102 rigidly secured to plate 54. Cylinder 60 is actuated to effect clockwise movement of drive pulley 72 against the bias of spring 96 to rotate spool 90 and invert metering mechanism 92 as hereinafter explained. The longitudinal axis of spool 90 serves as the pivot axis about which the metering mechanism 92 pivots.

Metering mechanism 92 comprises a body 104 (-FIG. 6) having a threaded bore 106 for receiving an externally threaded gauge tube generally designated I08, adjustably secured therein. Tube 108 is provided with a cavity IIO for receiving abrasive grit or particles as will hereinafter become apparent and which communicates with an inlet passage 112 and an outlet passage I14. Tube I08 is adjustable in body 104 to vary the volume of abrasive particles contained in cavity I10, as desired.

In order to allow easy adjustment of gauge tube 108 and to Since tube 108 fits loosely in bore 106, castellated lock nut! 113 is provided to maintain tube 108 in the desired position relative to bore I06. A slot I15 is provided in lock-nut ll3'to provided a passage for air pressure admitted between threads I05 and 107.

Inlet passage 112 is connected to one end of a conduit 116 by suitable coupling means, the other end of conduit 116 connected to the bottom of a storage hopper 118 secured to worktable 12. Inlet passage 112 communicates with a tube 117 which terminates in cavity 110 of gauge tube 108 and is secured in position by set screw 119. It is important that the outlet end of tube 117 terminates on the pivot axis i.e., the longitudinal axis of spool 90 about which gauge tube 108 pivots to accurately control the volume of abrasive particles discharged. ln this manner, tube 117 remains full when inverted and the possibility of discharging more or less than the measured volume of grit is eliminated.

A restriction or orifice 122 is provided at the open end of cavity 110 for metering the outward flow of abrasive particles at a predetermined rate. Outlet passage 114 is connected to one end of a delivery conduit 120 by suitable coupling means, the other end of conduit 120 being connected to discharge nozzle 52. A pair of diametrically opposed vent ports 124 and 126 (P10. 8) are provided in body 104 and connect outlet passage 114 to atmosphere to facilitate the feed of abrasive grit to discharge nozzle 52.

As shown in FIG. 1, a footoperated control valve 130 is connected by a pressure line 132 to a suitable source (not shown) of air under pressure. A conduit 134 connects valve 130 to a pressure regulator 136 which in turn is connected to a conduit 138 leading to cylinder 60. Air under the desired pressure is conveyed to discharge nozzle 52 by means ofa line 140 tapped into conduit 138 and generally coextensive with conduit 120.

Discharge nozzle 52 comprises a housing 142 having a venturi tube 144 therein with an inlet communicating with line 140 and an outlet 148. Tube 144 has a constricted portion forming a throat 150 and flaring wall 152 extending from throat 150 and diverging outwardly toward outlet 148. A port 154 opens into throat 150 and extends laterally outwardly through housing 142 and communicates with conduit 120. A cavity 156 extends about the outlet portion of tube 144 and is connected to an abrasive collecting bag 158 through passage 160. A yieldable, elastic collar 162 is suitably secured about the marginal edge of housing 142 and is adapted to engage the surface of the test specimens to confine dispersement of the spent abrasive particles and to permit recovery of the same through cavity 156 and passage 160.

In operation, a test specimen, such as an abrasive grinding wheel, is placed on its side on table 12. Nozzle 52 is swung into position by means of a parallelogram supporting arrangement with collar 162 brought into engagement with the side surface of the wheel. Let it be assumed that conduit 116 and gauge tube 108 are completely filled with abrasive particles which are fed by gravity from hopper 118. The operator depresses foot-operated control valve 130 to supply air under pressure to cylinder 60 for actuating piston 62 and connecting rod 66. Axial movement of rod 66 effects clockwise rotation of drive pulley 72 against the bias of coil spring 96 for rotating spool 90 through cable 88. The relative diameters of pulley 72 and spool 90 are such as to produce a 6 to 1 drive ratio, i.e. rotation of pulley 72 through 30 effects l80 rotation of spool 90. Accordingly, metering mechanism 92 is rotated 180 about the pivot axis defined by the spool 90 to an inverted position whereby the abrasive particles in gauge tube 108 are completely discharged into delivery conduit 120. Of course, orifice 122 restricts the flow of the particles from gauge tube 108 and can be varied in size to vary the flow rate, as desired.

Air is supplied via line 140 to inlet 146 of discharge nozzle 52. As the velocity of flow of air increases through throat 150, the pressure decreases to form a pressure differential between the airflow at throat 150 of nozzle 52 and atmospheric vent ports 124, 126 in metering mechanism 92, thus generating a suction force at throat 150 to convey the abrasive particles through delivery conduit 120 into nozzle 52 for blasting said particles against the test specimen. A significant feature of this invention is that mechanism 92 meters a predetermined volume of abrasive particles at a given rate through orifice 122 so that each test specimen is subjected to identical abrasive action. The spent abrasive particles are deflected back via cavity 156 and passage 160 into collecting bag 158 for processing and reuse. After the predetermined volume of abrasive particles have been used, the operator releases the foot operated control valve to interrupt the supply of air into the system. Spring 96 rotates drive pulley 72 in a counterclockwise direction to return metering device 92 to an upright position wherein abrasive particles are again fed by gravity into gauge tube 108 in preparation for the next cycle. The voids or depressions produced in the surface of the test specimen by the abrasive treatment are measured by any suitable indicating means (not shown) to determine the degree of wear of the specimen and its ability to resist abrasion.

From the foregoing it is seen that the present invention fully accomplishes its intended objects and provides an improved wear-testing apparatus having novel means for metering a charge of abrasive particles, which charge is blasted against a test specimen. In this manner, each specimen is subjected to the same abrasive treatment to determine its wear and abrasion resistance characteristics. By the provision of an adjustable gauge tube, the amount of the abrasive charge can be accurately measured within tolerable limits and by incorporating an orifice in the gauge tube, the rate of discharge flow ot'such charge can be precisely controlled. Moreover, the precise volume of abrasive grit discharged is insured by terminating the feed tube within the gauge tube at the axis about which the gauge tube pivots. An improved discharge nozzle is provided for directing a blast of abrasive particles against the test specimen, the discharge nozzle having a venturi tube for feeding the abrasive particles through the system. Also, means are provided for confining the abrasive particles to the blast area and for recovering the spent particles.

One form of the principles of this invention having been shown and described, it is to be understood that this has been done by way ofillustration only.

lclaim:

1. A metering apparatus comprising an elongated housing having a threaded bore; threaded means adjustably mounted in said bore and having a cavity therein for receiving solid particles; means for inverting said housing about an axis generally normal to the longitudinal axis of said housing to discharge said particles from said cavity; said cavity having an outlet through which said particles are discharged; and a restriction in said outlet for controlling the rate of flow of said particles from said cavity.

2. A metering apparatus according to claim 1, wherein said housing has a passage connecting said cavity to a supply of said particles and a passage connecting said cavity to a delivery conduit.

3. A metering apparatus according to claim 2, wherein said supply passage includes a tube having an outlet end terminating at said axis about which said housing is inverted.

4. A metering apparatus according to claim 1, wherein at least one port establishes communication between said cavity and ambient atmosphere.

5. A metering apparatus according to claim 1, wherein said inverting means comprises a pneumatic cylinder and a drive means interposed between said pneumatic cylinder and said housing.

6. A metering apparatus according to claim 1, wherein said adjustably mounted means comprises a gauge tube having external threads.

7. A metering apparatus according to claim 6, wherein said external threads of said gauge tube are mated with a threaded bore in said housing, said external threads and said threaded bore defining a spiral passage therebetween and power means for introducing air under pressure into said spiral passage for ejecting foreign particles therefrom.

8. A metering apparatus comprising: a housing having a threaded bore; means adjustably mounted in said bore and between said power means and said housing; said drive means comprising a drive pulley actuated by said power means, a rotatable spool rigidly connected to said housing, and a drive cable trained about said drive pulley and said spool. 

1. A metering apparatus comprising an elongated housing having a threaded bore; threaded means adjustably mounted in said bore and having a cavity therein for receiving solid particles; means for inverting said housing about an axis generally normal to the longitudinal axis of said housing to discharge said particles from said cavity; said cavity having an outlet through which said particles are discharged; and a restriction in said outlet for controlling the rate of fLow of said particles from said cavity.
 2. A metering apparatus according to claim 1, wherein said housing has a passage connecting said cavity to a supply of said particles and a passage connecting said cavity to a delivery conduit.
 3. A metering apparatus according to claim 2, wherein said supply passage includes a tube having an outlet end terminating at said axis about which said housing is inverted.
 4. A metering apparatus according to claim 1, wherein at least one port establishes communication between said cavity and ambient atmosphere.
 5. A metering apparatus according to claim 1, wherein said inverting means comprises a pneumatic cylinder and a drive means interposed between said pneumatic cylinder and said housing.
 6. A metering apparatus according to claim 1, wherein said adjustably mounted means comprises a gauge tube having external threads.
 7. A metering apparatus according to claim 6, wherein said external threads of said gauge tube are mated with a threaded bore in said housing, said external threads and said threaded bore defining a spiral passage therebetween and power means for introducing air under pressure into said spiral passage for ejecting foreign particles therefrom.
 8. A metering apparatus comprising: a housing having a threaded bore; means adjustably mounted in said bore and having a cavity therein for receiving solid particles; means for inverting said housing to discharge said particles from said cavity; said cavity having a restricted outlet for controlling the rate of flow of said particles from said cavity; said inverting means comprising power means and a drive means interposed between said power means and said housing; said drive means comprising a drive pulley actuated by said power means, a rotatable spool rigidly connected to said housing, and a drive cable trained about said drive pulley and said spool. 